Dehydration detector using micro-needles

Abstract

Examples are generally described that include an array of micro-needles. A capillary may be coupled to the array of micro-needles and configured to receive fluid from at least a portion of the array. A conductivity sensor may be arranged to measure conductivity of the fluid within the capillary, and a pump may be arranged to move fluid through the capillary. A processor may arranged to receive signals indicative of conductivity from the conductivity sensor and identify a dehydration condition based at least in part on a change in the signals indicative of conductivity.

1 . An apparatus for use in detecting dehydration, the apparatus comprising:
 an array of micro-needles;   a capillary coupled to the array of micro-needles and configured to receive fluid from at least a portion of the array of micro-needles;   a conductivity sensor arranged to measure conductivity of the fluid within the capillary, wherein a change in conductivity of the fluid is indicative of dehydration; and   a pump positioned to move fluid through the capillary.   
     
     
         2 . The apparatus of  claim 1  wherein the fluid comprises plasma. 
     
     
         3 . The apparatus of  claim 1  further comprising a plurality of capillaries, each configured to receive fluid from the array of micro-needles. 
     
     
         4 . The apparatus of  claim 1  wherein the conductivity sensor comprises a pair of electrodes. 
     
     
         5 . The apparatus of  claim 4  wherein the pair of electrodes are embedded within the capillary. 
     
     
         6 . The apparatus of  claim 1  wherein the pump comprises an electroosmotic pump. 
     
     
         7 . The apparatus of  claim 6  wherein the electroosmotic pump comprises a pair of electrodes. 
     
     
         8 . The apparatus of  claim 1  further comprising a passive power source coupled to the conductivity sensor. 
     
     
         9 . The apparatus of  claim 1  wherein an inlet of the capillary contains fabric configured to filter fluid entering the capillary. 
     
     
         10 . The apparatus of  claim 1  wherein the pump is configured for continuous flow. 
     
     
         11 . A system for detecting dehydration in a live subject, the system comprising:
 a micro-needle assembly comprising:
 an array of micro-needles configured to draw fluid from the live subject; 
 a conductivity sensor positioned to measure a conductivity of the fluid; and 
 a pump configured to draw the fluid toward the conductivity sensor; and 
   a processor configured to receive conductivity measurements from the conductivity sensor, identify a change in the conductivity based at least in part on the conductivity measurements, and provide an indication of dehydration based at least in part on the identified change in the conductivity.   
     
     
         12 . The system of  claim 11  wherein the micro-needle assembly is worn by the subject. 
     
     
         13 . The system of  claim 11  further comprising an alarm arranged to receive the indication from the processor and provide a signal indicative of dehydration to the live subject. 
     
     
         14 . The system of  claim 11  further comprising a memory coupled to the conductivity sensor and configured to store the conductivity measurements. 
     
     
         15 . The system of  claim 14  wherein the processor is configured to receive the conductivity measurements from the memory. 
     
     
         16 . A method for monitoring a subject for dehydration, the method comprising:
 extracting a flow of fluid from the subject with an array of micro-needles;   monitoring the conductivity of the fluid; and   generating a signal indicative of dehydration responsive at least in part to a change of the conductivity of the fluid.   
     
     
         17 . The method according to  claim 16  wherein the fluid comprises plasma. 
     
     
         18 . The method according to  claim 16  wherein monitoring the conductivity of the fluid comprises applying a voltage across at least a portion of the fluid. 
     
     
         19 . The method according to  claim 16  further comprising generating an alarm signal based at least in part on the signal indicative of dehydration. 
     
     
         20 . The method according to  claim 16  wherein monitoring the conductivity of the fluid comprises continuously pumping the fluid across a conductivity sensor.